146 DISTRIBUTION OF EXTINCT ANIMALS. [PART II. 
large size, especially among the Edentata and American families 
of Rodents, are additional proofs of a very high antiquity. 
Yet many of these cave animals are closely allied to those 
which are found in North America in the Post-Pliocene deposits 
only, so that we have no reason to suppose the cave-fauna to _ 
be of much earlier date. But the great amount of organic 
change it implies, must give us an enlarged idea of the vast 
periods of time, as measured by years, which are included in 
this, the most recent of all geological epochs. 
Pliocene Period of Temperate South America.—We have now 
to consider the numerous remains of extinct animals found in 
various deposits in the Pampas, and in Patagonia, and a few in 
Bolivia. The age of these is uncertain; but as they are very 
similar to the cave-fauna, though containing a somewhat larger 
proportion of -extinct genera and some very remarkable new 
forms, they cannot be very much older, and are perhaps best 
referred at present to the newer portion of the Pliocene 
formation. 
Carnivora—The genus Machairodus or sabre-toothed tigers, 
represents the Felidze. There are several species of wolves 
(Canis); a weasel (Mustela); two bears of the Brazilian cave- 
genus Arctotherium; and the extinct European genus Hyenaretos. 
Ungulata.—There are two species of Hquus, found in the 
Pampas, Chili, and Bolivia; two of Macrauchenia, an extra- 
ordinary extinct group allied to the tapir and Palwotherium, but 
with the long neck, and general size of a camel. A second 
species found on the highlands of Bolivia is much smaller. 
A more recent discovery, in Patagonia, is the almost perfect 
series of teeth of a large animal named Homalodontotherium; and 
which is believed by Professor Flower, who has described it, to 
have been allied to Rhinoceros, and still more to the Miocene 
Hyracodon from North America; and also to present some 
resemblances to Macrauchenia, and though much more remotely, 
to the curious genus Vesodon mentioned further on. 
The Artiodactyla, or even-toed Ungulates, are represented by a 
species of Dzcotyles, or peccary, found in the deposits of the 
